1. Field of the Invention
The present invention relates to an image forming apparatus with a heat fixing device for electrophotography process, such as a copier, a printer, a facsimile and the like. More specially, the present invention relates to an image forming apparatus with a gloss control function and gloss control method for an image forming apparatus.
2. Description of Related Art
These days, a system structure in which a plurality of image forming apparatuses are connected to a network for making a productivity thereof as number of times as that of a case of using an image forming apparatus in standalone mode is implemented. This system structure provides a better outputting speed and contributes to productivity. However, when a color image forming apparatus is used, fixing properties are influenced by a fluctuation of components accuracy due to a wear of the components, temperature control accuracy and the like, and thereby there is a possibility of having a deficiency that is a gloss difference in an output image among each image forming apparatus.
Even in a case of singularly using an image forming apparatus, when image formations are continuously performed, while a temperature controlling unit controls the image forming apparatus to return to an initial temperature, there is a time delay for a heat to reach a fixing roller surface from a heat source. In particular, in a case of using an image forming apparatus having large number of copying pages per unit time, there is a large tendency of decreasing a temperature due to an insufficient heat supply. As a result, fixing properties between an output image at an initial stage where a temperature decrease does not occur, and an output image at a point where a temperature decrease occurs are different, whereby a gloss difference is generated.
Further, in addition to a preset temperature, according to a fluctuation of adding pressure by a heating roller and by a pressure roller, a fluctuation of a hardness of the heating roller, an error of a rotation speed of both the rollers and the like, an error in fixing properties may be generated for each image forming apparatus to be used, whereby there is a case of generating a gloss difference in an output image.
These deficiencies occur due to the fact that a toner for forming a color image has a large physical dependence on a heat and a pressure, compared to a toner for forming a monochrome image.
As an art corresponding to an object in the system, in which a plurality of image forming apparatuses are connected to a network, for example, JP-Tokukai-2003-39786A and JP-Tokukai-2003-140415A are known. In these conventional arts, a control of merging a glossiness of a specific image forming apparatus with a glossiness of another image forming apparatus is performed. However, since it is necessary to designate a specific image forming apparatus, an operation becomes more complicated and a flexibility of a gloss adjustment is decreased.